1. Institute of Applied and Physical Chemistry (IAPC)Center for Environmental Research and Sustainable TechnologyUniversity of Bremen Leobener Straße 6 28359 Bremen Germany
2. Institute for Chemistry and Biology of the Marine Environment (ICBM)University of Oldenburg Carl-von-Ossietzky-Straße 9–11 26111 Oldenburg Germany
3. Department of ChemistryUniversity of the Free State PO Box 339 Bloemfontein 9300 South Africa